A. Motor-generator set
B. Motor converter
C. Rotary converter
D. Mercury arc rectifier
A. low power factor
B. high power factor
C. zero power factor
D. none of the above
A. d.c. only
B. a.c. only
C. partly a.c. and partly d.c.
A. Illumination
B. Electrolysis
C. Variable speed operation
D. Traction
A. anode
B. cathode
C. shell bottom
D. mercury pool
A. Telephones
B. Relays
C. Time switches
D. All of the above
A. Synchronous motor
B. Squirrel cage induction motor
C. Slip ring induction motor
D. Any of the above
A. same
B. less
C. double
D. three times
A. 0.05 V to 0.2 V per cm length of the arc
B. 0.5 V to 1.5 V per cm length of the arc
C. 2 V to 3.5 V per cm length of the arc
D. none of the above
A. its ionization potential is relatively low
B. its atomic weight is quite high
C. its boiling point and specific heat are low
D. it remains in liquid state at ordi¬nary temperature
E. all of the above